From prior art, silicone oil-based lubricating films are known that have found use in diverse industries. Especially for parenteral pharmaceutical packaging, such as syringes and carpules, silicone oils are commonly used as lubricating film systems. For example, U.S. Pat. No. 4,767,414 A describes a method for reducing static and dynamic friction between sliding surfaces by applying a lubricating film to at least one of the surfaces. A low molecular weight silicone oil is applied to one of the surfaces. The silicone oil and the surface are treated by a plasma.
However, some biopharmaceutical products are intolerant to silicone oil, so that they do not exhibit sufficient stability in conventional siliconized packaging such as prefilled siliconized syringes. A known cause for this silicone oil intolerance is that silicone oil tends to form particles, thereby triggering a silicone oil-particle-induced protein aggregation.
Therefore, the market side is currently looking for new packaging solutions that enable to stably store biopharmaceuticals in a silicone-free, prefilled syringe system (“PFS=prefillable syringe”). This requires a new lubricating film system which meets the requirements on tribological properties for the friction partners syringe barrel/stopper, and at the same time exhibits only low surface interaction with the biomolecules of the drug formulation.
US 2004/0231926 A1 describes a method for producing a lubricating film, wherein the lubricating film is cured at atmospheric pressure, using among other things an atmospheric pressure plasma. Besides silicone oil-based coatings, perfluoropolyether-based lubricating films can be produced. However, the breakaway force or static friction of the latter films has proved to be higher than that of cured silicone oil films. Moreover, during an atmospheric pressure treatment, in particular in an atmospheric pressure plasma treatment, increased incorporation of gases, especially of reaction products of the plasma, into the film may occur.